SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9533af13ad018b0d92027b4faf5c7d67b4f93c97987d9bf02aefc8767ffaa290' 
  AND token = 'mfKtZxp4nU3XdJr17ZyNoAdUHQJPBqObAs2y92bktKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}